If I remember correctly, she was uncomfortable with the idea of being filmed in such apparel (sexy red lingerie), I believe it was said that she was so uncomfortable that at one point she broke down in tears, or something like that.

So, they got a body bouble and some shots of "Lana" in lingerie were really shots of her body double. You never see theKreuk's face, the shots were taken from the neck down, and that in acrobatic flip you don't see a face, they might have blurred it out or it just went too fast to make any recognition. Same goes when she comes out of the pool, no face shown. And every other shot after that, it's Kreuk from the neck up.

Nicodemus is episode 15 of season 1, which is available on DVD.

This last season (I've lost count, maybe the 4th?), I doubt she uses a double, she has seemed to have grown mature enough to be comfortable with her own body and sexuality. The shower scene, everyone should know what I'm talking about, she even bares her back. Prior to that, the silhouette thru the shower curtain I believe it's her, and even prior to that, she's bare naked covered in white silky sheets, leaves little to the imagination. Double? I think not [anymore].